Of a child's several developing systems, no other has so profound an impact on his or her total developmental progress as a healthy communication system. Early detection of a deficit in the acquisition of communicative skills is essential because primary language learning is nearly complete by five years of age. Deficits which remain after that age are progressively less responsive to remedial intervention. Unfortunately, while most children are screened for visual or hearing impairment, only a small proportion are screened for communicative disorders. The most common reason for not employing current communicative tests is that they are too time consuming. Accordingly, it would be extremely desirable to have a rapid means for carrying out such tests.
One hearing test device that utilizes words as stimuli has been developed. This instrument was called the Verbal Auditory Screening for Children (VASC). See G. Mecher and B. McCulloch, Journal of Speech and Hearing Disorders 35, 241-247 (1970); B. Ritchie and R. Merklein, Journal of Speech and Hearing Research 15, 280-286 (1972). In the VASC system, the subject may be asked to identify a picture corresponding to the word presented from a group of pictures, but the subject is not scored for speech and language and the subject's "internal grammar" is not checked for completeness.
U.S. Pat. No. 3,745,674 to Thompson concerns an apparatus for testing the ability of a literate human to distinguish and associate among audio and multiple visual stimuli. Subjects are presented, in synchronization, a sound and a plurality of scenes upon a visual screen, the sound corresponding to one of the scenes presented. The subject responds by selecting a scene and activating a switch which corresponds to the scene selected. The subject is not required to vocalize a phrase presented, and there is no means provided to score the subject's vocalization. The use of masking noise is not suggested. In short, this patent does not describe an apparatus which tests a subject's complete communication system, along with the verbal and visual systems.
U.S. Pat. No. 4,862,005 to Keith et al. discloses an audiometer with an interactive graphic display for testing children. This patent simply describes an audiometer which provides changeable visual reinforcement of favorable responses for the detection of tones, rather than multiple visual images from which the child must choose in response to verbal stimuli. Thus, this apparatus is simply a hearing test, and provides no means to test the subject's communication system.
Another approach to testing hearing is known as SPIN (Speech Perception in Noise). See Kalikow et al., J. Acoustic Soc. America 61, 1337-1351 (1977); Bilger et al., Journal of Speech and Hearing Research 27, 32-48 (1984). SPIN simulates background conversation speech noise with a "masking" procedure known as babble. In this procedure, the subject is asked to repeat a word presented and the ability to discriminate a picture which corresponds to the word is not tested. The procedure is particularly useful in hearing aid adjustment, but does not provide and is not intended to provide a complete screening test of the communication system.
None of the foregoing tests provides a means for screening young children for communication problems. Accordingly, an object of the present invention is to provide such an apparatus.
Another object of the present invention is to provide a means for screening children for developmental disabilities of the communication system in as routine a manner as visual and hearing screenings are currently conducted.
Another object of the present invention is to provide a means for rapidly determining whether a child should be referred for further diagnostic testing for communication disorders.